


Star x Horse Marco

by EZF



Category: Star vs. The Forces Of Evil
Genre: Animal Transformation, Bestiality, F/M, Large Breasts, Large Cock, Other, Pregnancy, Pregnancy Kink, Size Difference
Language: English
Status: In-Progress
Published: 2020-03-23
Updated: 2020-03-23
Packaged: 2021-02-28 23:08:45
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,930
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23285299
Author URL: https://archiveofourown.org/users/EZF/pseuds/EZF
Summary: When Star attempts to cure a sick Marco with a spell she didn't properly research things get naughty.
Relationships: Star Butterfly/Marco Diaz
Comments: 2
Kudos: 18





	Star x Horse Marco

**Author's Note:**

> So this is based on the first commission i ever got in my life. Started as a simple one piece and turned into something more.
> 
> The inspiration came from monster arm and the overall racism of mewni in the show. I got a Kentenko who has more experience writing stories than me to help write this up. So big shout out to him. I'll link his userpage at the end, if you are into hyper stuff he tends to go for that.
> 
> The art of this piece was done by the amazing Bermasin, i'll link his pixiv, newgrounds at the end of the chapter.  
> I'll also link the piece on new grounds for those who want to read the original shorter story that I got help writing up.
> 
> He does amazing work, but i know its not everyone's cup of tea so i would appreciate that people refrain from throwing hate his way, if you dont like it then don't got there. 
> 
> Other than that I hope this piece finds its audience.

It had been some time since Marco had come to live in Mewni alongside Star as boyfriend and girlfriend after beating Toffee. It took some adjusting and acceptance from her parents (although her dad was more supportive) but things were settling down for Mewni and Star.

  
Every day was an adventure they shared, unfortunately the latest one they had in the never zone had left Marco sick and confined to a bed due to the cold, while Star had eaten a strange berry that had caused her assets to swell to more than generous proportions.

  
Star was aimlessly pacing the halls of the castle her breasts wobbling with each step, the doctor had said it would take a week for Marco to recover.

  
A week of boredom, a week without being able to have fun with Marco. Star had tried to cheer him up and keep him company but in his current state he was in no shape to do or appreciate anything.

  
It was then that Star had a flash of inspiration, she had magic surely one of the spells she had noted down before the destruction of the big book of spells had something that could speed up Marco’s recovery.

  
Rushing to her room she grabbed her journal and began going through each page hoping to find something related to healing.

Finally she found something that seemed to fit the bill: “Equinus transformus”

  
The description read as: Make the target healthy as a horse.  
Elated Star sprinted back towards Marco’s room without finishing reading the rest of the description below.  
Bursting into Marco’s room with a kick to the door Star didn’t even give him a chance to ask what was going on.

  
Aiming her hand at Marco she chanted the spell “Equinus transformus”.  
Marco could only scream as Star blasted him with a spell that she most likely did not know the full consequences of, but also that simply didn’t sound right.  
A flash of light engulfed the room as the spell connected forcing Star to close her eyes.

When the light finally faded and Star was able to look where Marco used to be, all she saw was a horse. This looked like an ordinary horse except for a few crucial details:  
It had Marco’s trademark hair style on his head, his cute little mole on his cheek and lastly it had his now highly stretched clothes on him.

Star could only blankly stare at her now transformed friend who for his part was clearly having a panic attack despite only neighs coming out of his mouth.  
“Soooooo I think the spell makes you healthy as a horse, by literally turning you into one. Well I’m sure that I can find a way to reverse the spell so just try to stay calm Marco.” Star cautiously uttered.

No sooner had she finished saying that, when Marco suddenly galloped forward. He went right through the wall in a rain of bricks sending him down onto the roof of a nearby house, before galloping off into the forest. Shortly afterward Star managed to recover from her shock to actually give chase.

  
Once Star’s mind finally started working again she realized that she had a couple of problems:

  
1) She had to find Marco who was god knows where in the forest

  
2) She had to find a cure to his condition

  
3) She was going to have to explain this to her mom

Deciding that right now finding Marco and bringing him back took priority, Star rushed out of the castle ignoring the guards that sought to question her as to why there was a giant hole in the wall.

  
In a few short minutes Star had run out of the castle and into the Streets of Mewni, the trail of Marco’s passage was obvious from the hoof marks the knocked down stalls and the confused people wondering what just barreled past them.  
Following the tracks left by his hooves she ran as fast as her legs could carry her, Marco had the advantage of speed due to his transformation. It took around an hour for Star to reach the outskirts of the forest and true to her nature she charged in without a second thought.

  
“After all how hard could it be to find something that big in the forest?”

Star wanted to hit herself for thinking that, it had been hours since she entered the forest and still no sign of Marco. She had followed the tracks until they had vanished, no matter how much she search she couldn’t find new ones.  
She desperately wanted to keep searching for Marco but she was getting nowhere on her own.

  
“Maybe I should go back to mom and explain everything, at least she could get the guards to help. But she’s probably gonna ground me for a month for this mess up.”

  
Her mind was pulled from her dilemma by a tingling feeling, the kind that you feel when someone is watching you. Slowly turning around Star was greeted by the sight of Marco staring at her.  
“Marco your back!” Star couldn’t contain her joy as her boyfriend found her instead. She wanted to jump into his chest and give him the strongest hug she could give, however, the way he stared at her gave her pause.  
She knew that look, it was the kind of look Marco gave her when he wanted to get intimate but this was far more intense, almost bestial. The large equine shaft bulging in his pants begging for relief confirmed her suspicions, Marco was in the mood for some love.

Had it been anyone else her answer would have been a definite no, but the way Marco’s gazed at her made her feel hot. She couldn’t deny that she was curious enough to want give his new body a tryout.  
She approached him slowly, sauntering to him putting motion into her hips, causing her butt to jiggle with each step. She did the same with her upper body her bountiful breasts waving side to side like hypnotic pendulums.

  
As she came to his head she grabbed it gently and pulled him close allowing him to bury it in her enlarged bosom. She felt his hot breath as he greedily inhaled her scent, Star kissed his forehead before she pulled away to keep moving. He turned his head to watch her jiggling booty cheeks.

  
As she walked around him she laid a hand on his body, feeling the muscles underneath as she approached his pants and crouched so that she was now partially underneath him. She could see it bulging inside his pant and couldn’t help but marvel at how his pants hadn’t torn open from the pressure the equine monster was exerting.

  
Cautiously she reached for the top part of his pants and slowly began to pull them off, of course Marco was more than happy to cooperate. Finally they came of letting the beast loose, along with it came to large swinging orbs underneath clearly filled to the brim.  
Despite her clear interest Marco made no attempt to take things further, instead he let Star get a good look practically posing for her to admire what he had to offer. Even after his transformation it was still the same Marco that she trusted completely.

“So want my help taking care of that Marco?” Star whispered in a sultry tone.

  
Marco’s lustful smile was the answer she received. With her mind made up she used her magic to conjure a stand for Marco to rest his front legs on. Walking over to it with Marco close behind, his throbbing acking cock clearly visible bobbing up and down with each step. With a snap of her fingers she felt the air against her now bare pussy as her underwear was magically whisked away.

  
Bending over underneath it she gripped it with her hands in anticipation of what was to come. Her bare moist pussy was all the invitation he needed as he eagerly positioned himself over her.  
Star could feel his equine shaft pressing against her entrance, she expected a single intense thrust but instead he slowly inched himself inside her. She could feel it all, every inch he claimed sending jolts throughout her body as her womb opened more and more allowing him to enter further and further.

Finally with one last jolt that sent her over the edge as he had hilted himself completely inside her. Her stomach bulged from his size, yet it didn’t hurt one bit all she felt was intense pleasure.  
Her legs nearly turned to jelly almost collapsing from the sheer pleasure, her eyes rolled while her womb clenched down on Marco’s cock. All it had taken was that gentle thrust to give her an orgasm so mind numbingly good she nearly passed, in fact she was certain the only reason she stayed up was Marco’s cock stood firm inside her keeping her from collapsing.

Once she had recovered from her first orgasm Marco started to move in gentle, smooth motions causing her entire body to burn hot with desire. Every time he pulled out she felt a sudden emptiness only for him to come pushing back in stuffing every part of her womb with his shaft.

  
Bit by bit Marco picked up the pace, the pleasure filled moans of Star seemed to egg him on, proud in the pleasure he brought her. What had started as a gentle motion had turned into an intense smashing of flesh. His swinging balls slapped against her ass while his length ravished her insides sparing nothing.

  
Star was in heaven, orgasm after orgasm assaulted her mind and body. The pleasure was mind numbingly intense she never thought this level of pleasure was possible. All her worries melted away with her rational mind, all that mattered were her and Marco.  
As Marco started thrusting even harder than before she could sense his coming orgasm, she felt her partners rising ecstasy as his dick began to grow even bigger bulging as it prepared to release the tide of cum pent up in his sack. Her body burned with even greater desire, demanding she allow him to finish inside her, her pussy clamped down on his cock refusing to give him a chance to pull out.

  
Each thrust affirmed that the two were more than friends, they were lovers. Her heart belonged to him, nothing and no one would tear her from him. If they did she would do anything to get back to him.  
Finally Marco erupted inside her, she felt his cock pumping her with a veritable deluge of cum.

Her dress tore as her stomach swelled to accommodate his seed while her mind was drowned in a pleasure even more intense than before sending her over the edge once more. The tide seemed endless, she didn’t know how long it lasted but Star eagerly accepted it all. Finally it stopped, yet his cock remained erect. Star couldn’t believe what she had experienced, it was naughty beyond imagining and she loved every second of it.

[ ](https://art.ngfiles.com/images/903000/903796_ber00_star-x-horse-marco-star-vs-the-forces-of-evil.png?f1557769639)

  
However, Marco didn’t seem done quite yet, his shaft still ached with desire to be tended to while his balls were weighed down by unspent seed waiting for a welcoming womb.  
She saw his head lower and just like his monstrous cock it was clear he wanted to go for another round. Eyeing her with a begging expression Star knew that he was giving her the choice to go for round or not.  
Star’s heart couldn’t help but beat faster, here was the man of her dreams having made her experience the most mind boggling orgasms she ever had and he still wanted more of her. Even better he still considered her desires, anyone else would have continued heedless of her consent. There was no way she would deny herself that pleasure nor would she deny Marco access to her body.

“Fine Marco… giddy up… let me have it all!” Star moaned in between gasps.

A smile crept onto Marco’s face as he straightened his head back up and began once more to move his hips, increasing in speed and intensity with each thrust. Star’s only hoped that her body could last as long as Marco’s….

Hours later both partners were basking in the afterglow of their intense mating session. Star’s stomach had swelled only slightly more than before as most of Marco’s seed failed to find room in her stuffed oven and fell onto the forest floor leaving a large puddle of equine cum underneath her.

  
Star’s legs had given in a long time ago leaving her held up only by Marco’s erection. Every inch of her body tingled from the assault, she couldn’t even find the breath to say anything only heavy breathes could be heard as both tried to recover from their workout.

  
His bestial desires satisfied Marco began to backpedal pulling out his shaft from inside Star, a delighted squeal signaled the coming of another orgasm from Star. Finally with a pop his cock was free and Star allowed herself to collapse onto the forest floor, lovingly Marco brought his head down to Star who gladly wrapped them around his thick neck as he lifted her up.

  
Now thinking clearly she felt the weight of his seeding sloshing inside her causing her to wonder if it had been a good idea to let him fill her with some much cum. She didn’t know if pregnancy was a risk given his transformation but if it was, it was no longer a possibility but rather a certainty.

  
Her mind flashed with images of herself, her stomach gravid with life, her breasts filled with milk to feed the unborn children. The thought sent jolts of electricity throughout her body, she mentally hoped it would take regardless of the consequences that would come with it. From the way Marco had lowered his head and was showering her stomach with kisses and long sensual licks of his large tongue, he seemed to be hoping for the same thing.

She realized she didn’t want to turn Marco back to normal. She was thoroughly addicted to the pleasure he had showed her, living without it would be hell but was it right to leave Marco in this state for her own selfish pleasure?  
Letting go of his neck Star stood on her own, her mind locked by the moral dilemma she faced. A series of neighs caught her attention, turning around she saw that Marco had found himself a puddle on the ground and was happily posing in front of it checking himself out. It was clear he liked the new him just as much as Star did.

  
“Well that’s one problem solved” Star softly muttered to herself.

  
Realizing her mother would never allow this union Star resolved to stay hidden away with Marco.  
Walking over to Marco she gently grabbed his head and pulled it against hers, their eyes locked together. The hint of worry in her eyes made Marco realize the seriousness of what she was about to say.

  
“M-marco, I wanted to ask you… Do you want to stay as you are?”

  
A gentle nodded was Marco’s answer.

  
“Then would you be willing to live here with me, mom wouldn’t allow this to continue and I don’t want that. So… I thought we could hide out here, if you are ok with that.”

  
Marco gently pulled himself from Star’s embrace and pressed his lips against her, Star eagerly accepted the show of affection putting her worries at ease.  
Breaking their kiss and their minds made up they walked side by side further into the forest, Marco hungrily gazed at Star’s ample bosom while Star lustfully eyed his large shaft and the bountiful orbs that dangled underneath. It wouldn’t be long before they would be indulging in each other, all they had to do was find themselves a nice quiet place.

Six months later, deep within the forest a rhythmic sound could be heard echoing through the woods. If one were to follow that noise they would come across Star and Marco once again in a passionate mating session just like the first time they explored their new bodies. Except that this time it would be princess Star that had changed.

  
Her stomach had swollen tremendously as she bore triplets, it had started as a slight swelling easily mistaken for the usual inflation she got from Marco’s affection. Yet each day it kept getting bigger confirming their suspicions, they should have been worried considering the unique situation of their conception. Yet Star only felt joy and pleasure at her new figure, she loved to lovingly stroke her now sensitive belly as she felt life move inside.

  
Marco for his part seemed to love her new figure and the idea that was going to be a father soon, he had grown highly protective of her chasing away any remotely dangerous animal and showering her stomach with tender licks whenever he could find a moment with her.

  
Both knew that the forest was no place to raise children and as they were inexperienced in child raising staying in the comfy cave they found was not an option. This meant they would have to go back to Mewni at some point and face the consequences of the choices, but right now none of that crossed their minds. All those worrying thoughts were tossed aside as the two love birds were in their own little world.  
Their own little secret paradise.

**Author's Note:**

> Ber's Pixiv: https: //www.pixiv.net/en/users/4583713  
> Newgrounds: https://ber00.newgrounds.com/  
> Pic on newgrounds (for those who want the other story): https://www.newgrounds.com/art/view/ber00/star-x-horse-marco-star-vs-the-forces-of-evil
> 
> Kentenkos userpage: https://www.furaffinity.net/gallery/kentenko/


End file.
